Composite fiber membrane for hydrogen fluoride gas, method for producing, use, and method for regenerating

Abstract

The present application relates to hydrogen fluoride-containing waste gas treatment technical field, specifically relates to the composite fiber membrane of hydrogen fluoride removal gas, preparation method, purposes and regeneration method, the composite fiber membrane of hydrogen fluoride removal gas includes matrix layer and microporous membrane layer, the matrix layer is modified to the matrix material under heat pressing treatment by using the amino functional reagent dispersed in the matrix material inside, simultaneously, one end of the amino functional reagent is embedded in the microporous membrane layer, to make the matrix layer and the microporous membrane layer adhere, the composite fiber membrane of the present application filters aerosol particles through the microporous membrane layer, effectively removes the particulate matter or aerosol in hydrogen fluoride removal gas, and the amino fiber of the matrix layer is high-efficiency and fast adsorption hydrogen fluoride gas, the matrix material is modified under heat pressing condition by the amino functional reagent, realizes the close adhesion of the matrix layer and the microporous membrane layer, improves the removal efficiency of fluorine, solves the problem that the existing adsorption material is interfered by particulate matter or aerosol and leads to the low efficiency of hydrogen fluoride waste gas treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen fluoride-containing waste gas treatment, in particular to a composite fiber membrane for removing hydrogen fluoride gas, a preparation method, use and regeneration method thereof. BACKGROUND

[0002] In the chemical industry, hydrogen fluoride is widely used in smelting, fluoride product processing, glass manufacturing, semiconductor production, and solar cell manufacturing, as an important raw material and intermediate. However, the widespread use of hydrogen fluoride also brings serious environmental pollution and health risks. Hydrogen fluoride is a colorless and odorless toxic inorganic gas under normal conditions, which has strong corrosive properties and can cause great harm to the skin, mucous membranes and respiratory system of the human body. Acute exposure to hydrogen fluoride can cause deep chemical burns, forming stubborn necrosis or ulcers, and even cause acute poisoning death when the concentration of hydrogen fluoride is 400mg / m 3 430mg / m 3 Under, even cause acute poisoning death. When exposed to low-concentration hydrogen fluoride environment for a long time, serious health problems such as inflammation of the eyes, nose, throat, nervous system symptoms, and bone damage may occur.

[0003] In addition, the emission of hydrogen fluoride gas into the atmosphere can also cause acid rain, causing long-term damage to soil, water sources and ecosystems. Based on this, how to effectively treat hydrogen fluoride pollutants, especially hydrogen fluoride-containing aerosol waste gas, has become an important issue to be solved in the industry and environmental protection field.

[0004] At present, the methods for treating hydrogen fluoride waste gas in industry mainly include water and lye absorption method, activated carbon absorption method, γ-Al2O3 absorption method, calcium oxide absorption method, hydrotalcite absorption method, etc. The above treatment methods mainly use water, lye, activated carbon, γ-Al2O3, calcium oxide, hydrotalcite and other adsorption materials to adsorb hydrogen fluoride. However, since the hydrogen fluoride waste gas often contains particulate matter or aerosol, the presence of these particulate matter or aerosol will interfere with the adsorption effect of the existing adsorption materials on hydrogen fluoride, resulting in the problem of low efficiency of hydrogen fluoride waste gas treatment. SUMMARY

[0005] In order to solve the problem that the existing adsorption materials are interfered by particulate matter or aerosol and result in low efficiency of hydrogen fluoride waste gas treatment, the purpose of the present application is to provide a composite fiber membrane for removing hydrogen fluoride gas and a preparation method and regeneration method thereof.

[0006] To achieve the above-mentioned purpose, the technical solutions of the present application are as follows.

[0007] The first aspect of the present application provides a composite fiber membrane for removing hydrogen fluoride gas, comprising a base layer and a microporous membrane layer; the base layer is obtained by modifying the base material with an amino functional agent dispersed inside the base material under heat pressing treatment; meanwhile, one end of the amino functional agent is embedded in the microporous membrane layer to bond the base layer and the microporous membrane layer; the base material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the content of acrylonitrile monomer in the base material is 10wt%-99wt%; and the amino functional agent is an amine compound containing at least two amino groups.

[0008] The composite fiber membrane of the present application filters aerosol particles through the microporous membrane layer, effectively removes particulate matter or aerosol in hydrogen fluoride gas, and simultaneously absorbs hydrogen fluoride gas through the amino fiber of the base layer. In addition, the present application modifies the base material with the amino functional agent under heat pressing conditions, which not only improves the utilization efficiency of the amino functional agent, but also realizes the close bonding of the base layer and the microporous membrane layer, thereby further improving the overall fluorine removal efficiency and solving the problem that the existing adsorption material is disturbed by particulate matter or aerosol, resulting in low efficiency of hydrogen fluoride waste gas treatment.

[0009] The present application uses amino functional agents for modification, and replaces the adhesive between the base layer and the microporous membrane layer, thereby improving the utilization efficiency of the amino functional agent.

[0010] Preferably, the base material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the amino functional agent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethylenheptamine and p-phenylenediamine; the microporous membrane material used in the microporous membrane layer is any one of polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane and polyvinylidene fluoride microporous membrane; and the pore size of the microporous membrane material is 0.1-1 microns.

[0011] In the present application, the base material is preferably polyacrylonitrile fiber or amino polyacrylonitrile fiber, wherein the content of acrylonitrile monomer in the base material is greater than 10wt%; the amino polyacrylonitrile fiber is an amino functional fiber obtained by pre-modifying polyacrylonitrile fiber with an amino functional agent, and the specific preparation method can refer to CN114042437B.

[0012] Preferably, the ion exchange capacity of the composite fiber membrane is 1mmol / g-6mmol / g; and the resistance of the composite fiber membrane is <250Pa when the air linear velocity is 5.33cm / s. Preferably, the ion exchange capacity of the composite fiber membrane is 3mmol / g-6mmol / g; and the resistance of the composite fiber membrane is <120Pa when the air linear velocity is 5.33cm / s.

[0013] The second aspect of the present application provides a preparation method of a composite fiber membrane for removing hydrogen fluoride gas, comprising the following steps:

[0014] The base material is placed in a solution containing an amino functional agent to swell the base material sufficiently to obtain a swollen base material; the base material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the content of acrylonitrile monomer in the base material is 10wt%-99wt%; the amino functional agent is an amine compound containing at least two amino groups; a microporous membrane material is covered on the swollen base material, and heat pressing treatment is performed to modify the base material by using the amino functional agent, and meanwhile, one end of the amino functional agent is embedded in the microporous membrane layer to bond the base layer and the microporous membrane layer to obtain the composite fiber membrane for removing hydrogen fluoride gas.

[0015] The composite fiber membrane prepared by the present application mainly uses an amino functional agent to modify the base material, and bond the base layer and the microporous membrane layer. The amino group on the amino functional agent reacts with the cyano group in the base material to enable part of the amino functional agent to form a structure with one end grafted to the base material and the other end embedded in the microporous membrane pores, which are bonded by chemical bonding force and physical bonding force.

[0016] In addition, the present application uses heat pressing treatment to bond the base layer and the microporous membrane layer, and at the same time, improves the grafting degree of the fiber, greatly shortens the preparation time of the composite fiber membrane, and improves the production efficiency.

[0017] Preferably, the base material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the amino functional agent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethylenheptamine, and p-phenylenediamine; the microporous membrane material used in the microporous membrane layer is any one of polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane, and polyvinylidene fluoride microporous membrane; the pore size of the microporous membrane material is 0.1 μm-1 μm; and the resistance of the microporous membrane material is <200 Pa at an air linear velocity of 5.33 cm / s.

[0018] Preferably, the resistance of the microporous membrane material is <100 Pa at an air linear velocity of 5.33 cm / s.

[0019] Preferably, the heat pressing treatment is performed at a temperature of 60°C-140°C, a time of 1 min-120 min, and a pressure of 0 MPa-30 MPa. Preferably, the heat pressing treatment is performed at a temperature of 80°C-110°C, a time of 1 min-60 min, and a pressure of 0 MPa-10 MPa.

[0020] In the present application, the modification is carried out at 60℃ or above, and no reaction occurs at normal temperature swelling.

[0021] Preferably, the solution containing the amino-functional reagent is obtained by dissolving the amino-functional reagent in a solvent; the mass concentration of the amino-functional reagent in the solution containing the amino-functional reagent is 1% to 50%; the solvent is at least one of water, methanol, ethanol, propanol, butanol, ethylene glycol and propylene glycol; and the mass percentage of the solvent in the swollen matrix material is 10% to 60%.

[0022] Preferably, the mass concentration of the amino-functional reagent in the solution containing the amino-functional reagent is preferably 5% to 40%, further preferably 20% to 40%, and further preferably 20% to 30%.

[0023] Preferably, the mass percentage of the solvent in the swollen matrix material is 10% to 30%.

[0024] The third aspect of the present application provides a use of the composite fiber membrane for removing hydrogen fluoride gas as a fluorine ion adsorption material in the treatment of hydrogen fluoride gas.

[0025] Preferably, the hydrogen fluoride gas contains hydrogen fluoride aerosol with a particle size of 0.3μm to 1μm.

[0026] The composite fiber membrane of the present application has a treatment efficiency of more than 99% for fluorine-containing hydrogen particles with a size of 0.3μm or more, and a treatment efficiency of more than 99% for 100mg / m 3 The purification efficiency of the hydrogen fluoride gas is more than 99%.

[0027] The fourth aspect of the present application provides a regeneration method of the composite fiber membrane for removing hydrogen fluoride gas according to the first aspect, comprising the following steps:

[0028] The regeneration solution is an inorganic alkali solution with a mass concentration of 0.5% to 10%; the used composite fiber membrane is soaked in the inorganic alkali solution, or the inorganic alkali solution is sprayed on the used composite fiber membrane; and the inorganic alkali in the inorganic alkali solution is any one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

[0029] Preferably, the regeneration solution is an inorganic alkali solution with a mass concentration of 0.5% to 3%.

[0030] The regeneration method of the composite fiber membrane provided by the present application can be selected from on-line spraying regeneration without stopping or soaking regeneration with stopping, has the characteristics of fast regeneration speed and simple regeneration method, and the on-line regeneration without stopping is suitable for industrial continuous operation.

[0031] The present application has the following beneficial effects:

[0032] 1. The composite fiber membrane of the present application mainly combines the characteristics of low resistance and high efficiency of filtering particulate matter of the microporous membrane layer and the characteristics of sensitive and high efficiency of adsorbing hydrogen fluoride of the multi-amino functional fiber of the base layer, and simultaneously modifies the base material under the condition of hot pressing by using the amino functional reagent, thereby not only improving the utilization efficiency of the reagent, but also realizing the close adhesion of the base layer and the microporous membrane layer, greatly improving the defluorination efficiency of the composite fiber membrane, and solving the problem that the existing adsorption material is interfered by particulate matter or aerosol, thereby resulting in low efficiency of treating hydrogen fluoride waste gas.

[0033] 2. The composite fiber membrane of the present application has a treatment efficiency of more than 99% for 0.3 μm or more hydrogen fluoride-containing particles, and a treatment efficiency of more than 99% for 100 mg / m 3 The purification efficiency of hydrogen fluoride gas is more than 99%.

[0034] 3. The composite fiber membrane prepared by the present application mainly uses the general formula of the amino functional reagent to modify the base material and adhesively bond the base layer and the microporous membrane layer. The amino group on the amino functional reagent reacts with the cyano group in the base material, so that part of the amino functional reagent can form a structure with one end grafted to the base material and the other end embedded in the microporous membrane hole, and the structure is adhesively bonded by chemical adhesion and physical adhesion.

[0035] 4. The present application adopts the method of hot pressing to prepare the composite fiber membrane, adhesively bonds the base layer and the microporous membrane layer, improves the grafting degree of the fiber, greatly shortens the preparation time of the composite fiber membrane, improves the production efficiency, has the characteristics of low cost, simple preparation process, and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic diagram of the composite fiber membrane provided by an embodiment of the present application.

[0037] Figure 2 is a schematic diagram of a hydrogen fluoride purification and adsorption experimental device of the composite fiber membrane.

[0038] Figure 3 is a graph of the removal rate of the composite fiber membrane of an embodiment of the present application for hydrogen fluoride gas or particulate matter of 0.3 μm or more with the change of the regeneration number.

[0039] Figure 4 is an infrared spectrum diagram of the base material before and after treatment in Example 1 of the present application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0041] All other embodiments obtained by those of ordinary skill in the art without creative labor based on the embodiments of the present application fall within the scope of protection of the present application.

[0042] As Figure 1 The present application provides a composite fiber membrane for removing hydrogen fluoride gas, which comprises a base layer and a microporous membrane layer; the base layer is obtained by modifying a base material with an amino functional agent dispersed in the base material under heat pressing treatment; meanwhile, one end of the amino functional agent is embedded in the microporous membrane layer to bond the base layer and the microporous membrane layer; the base material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the content of acrylonitrile monomer in the base material is 10wt%-100wt%; and the amino functional agent is an amine compound containing at least two amino groups.

[0043] The preparation method of the composite fiber membrane for removing hydrogen fluoride gas of the present application mainly uses polyacrylonitrile fiber or amino polyacrylonitrile fiber as the base, one or more polyamine compounds selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethylenheptamine and p-phenylenediamine as the amino functional agent, and microporous membranes such as polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane and polyvinylidene fluoride microporous membrane as the membrane layer material. First, the base is placed in an amino functional agent solvent for sufficient swelling, and then the excess solvent is removed. The swelled base material is overlaid with the membrane layer material, and then hot pressing treatment is performed using a flat plate hot press without or with a small amount of hot melt adhesive. After the hot pressing treatment, washing and drying are performed to obtain the composite fiber membrane for removing hydrogen fluoride gas.

[0044] Among them, the polypropylene microporous membrane is denoted as PP microporous membrane; the polyester microporous membrane is denoted as PET microporous membrane; the polyamide microporous membrane is denoted as PA microporous membrane; the polytetrafluoroethylene microporous membrane is denoted as PTFE microporous membrane; and the polyvinylidene fluoride microporous membrane is denoted as PVDF microporous membrane.

[0045] The present application also provides a use and a regeneration method of the composite fiber membrane for removing hydrogen fluoride gas. The composite fiber membrane for removing hydrogen fluoride gas has high sensitivity, high removal rate, small system resistance, easy regeneration and other advantages, and can be operated continuously for a long time, and is suitable for treating hydrogen fluoride gas in various fields and of various scales. The preparation method of the present application has the advantages of wide availability of raw materials, low cost, simple process, and is suitable for large-scale industrial production and use, especially for the semiconductor manufacturing industry and other industries that require high-precision treatment of hydrogen fluoride gas.

[0046] It should be noted that the composite fiber membrane prepared by the present application mainly uses an amino functional reagent to modify the general formula of the matrix material, bond the matrix layer and the microporous membrane layer. Among them, the amino group on the amino functional reagent reacts with the cyano group in the matrix material, so that part of the amino functional reagent can form a structure with one end grafted to the matrix material and the other end embedded in the microporous membrane hole, which is bonded by chemical bonding force and physical bonding force. The reaction between the amino group on the amino functional reagent and the cyano group in the matrix material is carried out at a temperature of 60°C or higher, and does not occur at room temperature. The swelling step of the matrix material can be carried out at room temperature or 20-50°C, and the room temperature is 25°C±5°C.

[0047] The technical solutions of the present application will be further described below through specific examples.

[0048] In each of the following examples, the method is a conventional method unless otherwise specified; the reagents and materials, unless otherwise specified, can be purchased on the market.

[0049] Polyacrylonitrile fibers with acrylonitrile monomer content greater than 80wt% were purchased from Qilu Petrochemical.

[0050] The amino polyacrylonitrile fiber is self-made in the laboratory. The specific preparation method is reference patent application CN114042437B. The pH is neutral, i.e. pH=7.

[0051] Test equipment: fabric air permeability tester, Jinan Lanlight Mechatronics Co., Ltd., TQD-G1A. Flat plate hot press, Guangzhou Hale Technology Co., Ltd., HTYP-30. Aerosol generator, Qingdao Lubo Jianye Environmental Protection Technology Co., Ltd., LB-3311. Nondestructive testing system for filter absorber, Beijing Aerospace Yilai Electronics Technology Co., Ltd., VRD-FO1. The rest of the equipment is a commercial product unless otherwise specified.

[0052] Example 1

[0053] A preparation method of a composite fiber membrane for removing hydrogen fluoride gas, comprising the following steps:

[0054] Step 1, swelling of the matrix material: polyacrylonitrile fibers with acrylonitrile monomer content greater than 80wt% were selected as the matrix material, and the matrix material was placed in a 40% diethylene triamine aqueous solution, soaked at room temperature for 12h to make the matrix material fully swell, and after removing the excess solvent, the swollen matrix material was obtained. The mass percentage of the solvent contained in the swollen matrix material is 10%.

[0055] Step 2, preparation of the composite membrane for removing hydrogen fluoride gas: a layer of polypropylene microporous membrane is coated on the swollen matrix material. The pore size of the polypropylene microporous membrane material is 0.1 μm; the resistance of the microporous membrane material is < 100 Pa at an air linear velocity of 5.33 cm / s.

[0056] The matrix material coated with the polypropylene microporous membrane is heat-pressed using a flat-plate heat press at a temperature of 95°C and a pressure of 1 MPa for 60 min to modify the matrix material with the amino functional reagent, and meanwhile, one end of the amino functional reagent is embedded in the microporous membrane layer to bond the formed matrix layer and the microporous membrane layer. After the heat-pressing treatment, the fiber is washed with water until the pH is neutral, and dried at 60°C until the constant weight to obtain the composite membrane for removing hydrogen fluoride gas.

[0057] Figure 4 Fig. 1 is an infrared spectrum of the matrix material before and after treatment in Example 1. Among them, the commercially available polyacrylonitrile fiber is the matrix material before treatment; the modified polyacrylonitrile fiber after treatment is the matrix material after treatment by the method of Example 1.

[0058] As Figure 4 , the peak at 2242 nm is the nitrile group peak, and the peak intensity is weakened after treatment, which proves that the reaction with the nitrile group occurs. The peak at 3274 nm is the N-H stretching peak, and the peaks at 1635 nm, 1560 nm and 1237 nm are the C-N double bond and C-N single bond stretching peaks, which prove that the grafting is successful.

[0059] Example 2

[0060] A method for preparing a composite membrane for removing hydrogen fluoride gas, comprising the following steps:

[0061] Step 1, swelling of the matrix material: an amino polyacrylonitrile fiber with an acrylonitrile monomer content of more than 10 wt% is selected as the matrix material, and the matrix material is placed in a 20% triethylenetetramine ethylene glycol solution, and soaked at 50°C for 3 h to fully swell the matrix material. After removing the excess solvent, the swollen matrix material is obtained. The mass percentage of the solvent contained in the swollen matrix material is 10%.

[0062] Step 2, preparation of the composite membrane for removing hydrogen fluoride gas: a layer of polypropylene microporous membrane is coated on the swollen matrix material. The pore size of the polypropylene microporous membrane material is 0.1 μm; the resistance of the microporous membrane material is < 100 Pa at an air linear velocity of 5.33 cm / s.

[0063] The base material covered with the microporous membrane material is treated by hot pressing using a flat hot press at a temperature of 100°C and a pressure of 3Mpa for 20min, so as to modify the base material by using the amino functional reagent, and meanwhile, one end of the amino functional reagent is embedded in the microporous membrane layer, so as to bond the formed base layer and the microporous membrane layer. After the hot pressing treatment, the fiber is washed with water until the pH is neutral, and then dried at 60°C until the weight is constant, so as to obtain the composite fiber membrane without hydrogen fluoride gas.

[0064] Example 3

[0065] A preparation method of a composite fiber membrane without hydrogen fluoride gas, comprising the following steps:

[0066] Step 1, swelling of the base material: the amino polyacrylonitrile fiber with the acrylonitrile monomer content of more than 80wt% is selected as the base material, the base material is placed in a 20% diethylene triamine aqueous solution, and is soaked at 40°C for 12h to make the base material fully swell. After removing the excess solvent, the swollen base material is obtained. The mass percentage of the solvent contained in the swollen base material is 10%.

[0067] Step 2, preparation of the composite fiber membrane without hydrogen fluoride gas: a layer of polyvinylidene fluoride microporous membrane is covered on the swollen base material. The pore size of the polyvinylidene fluoride microporous membrane material is 0.1μm; and the resistance of the microporous membrane material is <100Pa when the air linear velocity is 5.33cm / s.

[0068] The base material covered with the microporous membrane material is treated by hot pressing using a flat hot press at a temperature of 100°C and a pressure of 3Mpa for 20min, so as to modify the base material by using the amino functional reagent, and meanwhile, one end of the amino functional reagent is embedded in the microporous membrane layer, so as to bond the formed base layer and the microporous membrane layer. After the hot pressing treatment, the fiber is washed with water until the pH is neutral, and then dried at 60°C until the weight is constant, so as to obtain the composite fiber membrane without hydrogen fluoride gas.

[0069] Comparative Example 1

[0070] A preparation method of a modified fiber, which is different from Example 1 in that a layer of microporous membrane layer is not covered on the base layer. The specific method comprises the following steps:

[0071] Step 1, swelling of the base material: the polyacrylonitrile fiber with the acrylonitrile monomer content of more than 80wt% is selected as the base material, the base material is placed in a 40% diethylene triamine aqueous solution, and is soaked at room temperature for 12h to make the base material fully swell. After removing the excess solvent, the swollen base material is obtained. The mass percentage of the solvent contained in the swollen base material is 10%.

[0072] Step 2, preparation of the modified treated fiber: the swollen matrix material is hot-pressed using a flat hot press at a temperature of 95°C and a pressure of 1 MPa for 60 min to modify the matrix material with the amino functional reagent to form a matrix layer. After the hot-pressing treatment, the fiber is washed with water until the pH is neutral, and dried at 60°C until the weight is constant to obtain the modified treated fiber.

[0073] Comparative Example 2

[0074] A method for preparing a modified treated fiber, which is different from that of Example 2 in that a microporous membrane layer is not covered on the matrix layer. The specific method comprises the following steps:

[0075] Step 1, swelling of the matrix material: an amino polyacrylonitrile fiber with an acrylonitrile monomer content of greater than 10 wt% is selected as the matrix material, and the material is placed in a 20% diethylene triamine aqueous solution, soaked at 50°C for 3 h to fully swell the matrix material. After removing the excess solvent, the swollen matrix material is obtained. The mass percentage of the solvent contained in the swollen matrix material is 10%.

[0076] Step 2, preparation of the modified treated fiber: the swollen matrix material is hot-pressed using a flat hot press at a temperature of 100°C and a pressure of 3 MPa for 20 min to modify the matrix material with the amino functional reagent to form a matrix layer. After the hot-pressing treatment, the fiber is washed with water until the pH is neutral, and dried at 60°C until the weight is constant to obtain the modified treated fiber.

[0077] Comparative Example 3

[0078] A method for preparing a hot-pressed microporous membrane, which is different from that of Example 1 in that no swollen matrix material is provided. The specific method comprises the following steps:

[0079] A polypropylene microporous membrane is selected, and the polypropylene microporous membrane is hot-pressed using a flat hot press at a temperature of 95°C and a pressure of 1 MPa for 60 min. After the hot-pressing treatment, the fiber is washed with water until the pH is neutral, and dried at 60°C until the weight is constant to obtain the hot-pressed microporous membrane.

[0080] Comparative Example 4

[0081] A method for preparing a composite fiber membrane for removing hydrogen fluoride gas, which is different from that of Example 1 in that no amino functional reagent is added. The specific method comprises the following steps:

[0082] Step 1, swelling of the matrix material: an amino polyacrylonitrile fiber with an acrylonitrile monomer content of greater than 80 wt% is selected as the matrix material, and the matrix material is placed in pure water and soaked at room temperature for 12 h to fully swell the matrix material. After removing the excess solvent, the swollen matrix material is obtained. The mass percentage of the solvent contained in the swollen matrix material is 10%.

[0083] Step 2, preparation of the hydrogen fluoride gas removal composite fiber membrane: a layer of polypropylene microporous membrane is coated on the swollen matrix material. The pore size of the polypropylene microporous membrane material is 0.1 μm; the resistance of the microporous membrane material is <100 Pa at an air linear velocity of 5.33 cm / s.

[0084] The matrix material coated with the polypropylene microporous membrane is hot-pressed using a flat hot press at a temperature of 95°C and a pressure of 1 MPa for 60 min. After the hot-pressing treatment, the fiber is washed with water until the pH is neutral, and then dried at 60°C to a constant weight to obtain the hydrogen fluoride gas removal composite fiber membrane.

[0085] Sampling test: the composite fiber membranes prepared in Examples 1-3 are used as samples 1, 2 and 3, respectively. The modified fiber prepared in Comparative Examples 1-2 is used as samples 4 and 5. The hot-pressed microporous membrane prepared in Comparative Example 3 is used as sample 6. The composite fiber membrane prepared in Comparative Example 4 is used as sample 7.

[0086] The dried samples 1-7 are tested for hydrogen fluoride removal rate and anion exchange capacity.

[0087] The test method for hydrogen fluoride removal rate is as follows:

[0088] A single fiber disc with a diameter of 6.0 cm and a weight of more than 1 g is accurately cut from the dried samples 1-7, and the fiber disc is placed in an adsorption column with an inner diameter of 5.2 cm. After being tightly fixed, the hydrogen fluoride removal performance of the composite fiber membrane and the combination of the composite fiber membrane and the regeneration solution is characterized by a dynamic adsorption experiment. The experimental device is shown in Figure 2 A certain concentration of hydrogen fluoride gas and fluorine-containing particulate matter mixed gas is passed through the composite fiber membrane material in the adsorption column for hydrogen fluoride purification adsorption experiment, and the relevant experimental data are recorded.

[0089] The determination method of anion exchange capacity is as follows:

[0090] Experimental group: before testing, the dried samples 1-7 are soaked in 0.5 mol / L NaOH solution for 6 h according to the liquid-solid ratio ≥100 / 1, washed to neutral, and dried. Then, 0.100 g of the sample and 50 mL of 0.1 mol / L hydrochloric acid solution are accurately weighed and added into a 100 mL conical flask, and then left to stand for 12 h. After that, the filtrate is obtained by filtration; 10 mL of the filtrate is removed and titrated with a standard sodium hydroxide solution.

[0091] At the same time, according to the above test method, a blank control group without adding the sample is prepared.

[0092] The ion exchange capacity calculation formula is: Q = (5 × (V0-V1) × C NaOH) / W; wherein Q is the anion exchange capacity of the sample, mmol / g; V0 is the volume of sodium hydroxide solution consumed by the blank control group, mL; V1 is the volume of sodium hydroxide solution consumed by the experimental group, mL; C NaOH is the concentration of the standard sodium hydroxide solution used for titration, mol / L; and W is the weight of the sample, g.

[0093] The test results are shown in Table 1.

[0094] Table 1 Test results of hydrogen fluoride removal rate and anion exchange capacity

[0095]

[0096]

[0097] Table 25 Test results of material resistance at 33 cm / s and observation results of bonding firmness

[0098]

[0099]

[0100] As can be seen from Table 1, the composite fiber membrane prepared by the preparation method of the embodiments of the present application has excellent removal efficiency for hydrogen fluoride gas and hydrogen fluoride aerosol in the air, and the maximum removal efficiency can reach more than 99%, and the composite fiber membrane prepared by the embodiments of the present application exhibits the characteristics of high sensitivity and high removal rate.

[0101] In contrast, the single aminopolyacrylonitrile fiber and the single microporous membrane in Comparative Examples 1 to 3 have poor removal effect on the mixture of hydrogen fluoride gas and hydrogen fluoride aerosol.

[0102] In Comparative Example 4, the simple hot-pressing treatment cannot tightly bond the substrate layer and the microporous membrane layer without using the polyamine reagent. However, when the polyamine reagent is used for bonding in the embodiments of the present application, the substrate material is further modified, which improves the anion exchange capacity of the composite fiber membrane without causing significant increase in resistance, which further highlights the importance of using the polyamine reagent to bond the substrate layer and the microporous membrane layer.

[0103] The composite fiber membranes prepared in Examples 1 to 3 were subjected to regeneration experiments.

[0104] Example 4

[0105] A regeneration method of a composite fiber membrane for removing hydrogen fluoride gas, comprising the following steps:

[0106] The composite fiber membranes prepared in Examples 1 to 3 were selected to adsorb hydrogen fluoride gas.

[0107] The sodium hydroxide solution with a mass concentration of 3% is used as the regeneration solution; the composite fiber membrane after adsorption saturation is regenerated by spraying the sodium hydroxide solution with a mass concentration of 3%, the spraying speed is spraying the composite fiber membrane with the same mass of the regeneration solution per second, and the spraying time is 5 minutes.

[0108] The experimental conditions of the adsorption-regeneration process are as follows:

[0109] Under normal temperature and pressure, the carrier gas is nitrogen. The hydrogen fluoride gas is 100 mg / m 3 , the fluorine-containing particulate matters above 0.3 microns are greater than 100000 pcs / L, the device Figure 2 is used for the experiment, the gas flow rate is 1 L / min, and each test lasts for 20 minutes.

[0110] The composite fiber membrane regenerated according to the regeneration method of Example 5 is subjected to the above adsorption-regeneration process repeatedly, and after 20 times of repetition, the removal rate of the composite fiber membrane to the hydrogen fluoride gas and the hydrogen fluoride aerosol does not decrease, as shown in Table 2. Figure 3 Thus, it is illustrated that the composite fiber membranes of Examples 1-3 have excellent regeneration performance and can be used repeatedly for many times.

[0111] Example 5

[0112] A regeneration method of a composite fiber membrane for removing hydrogen fluoride gas, comprising the following steps:

[0113] The composite fiber membranes prepared in Examples 1-3 are selected to adsorb the hydrogen fluoride gas.

[0114] The sodium hydroxide solution with a mass concentration of 3% is used as the regeneration solution; the composite fiber membrane after adsorption saturation is regenerated by immersing the composite fiber membrane in the sodium hydroxide solution with a mass concentration of 3% for 30 seconds.

[0115] The experimental conditions of the adsorption-regeneration process are as follows:

[0116] Under normal temperature and pressure, the carrier gas is nitrogen. The hydrogen fluoride gas is 100 mg / m 3 , the fluorine-containing particulate matters above 0.3 microns are greater than 100000 pcs / L, the device Figure 2 is used for the experiment, the gas flow rate is 1 L / min, and each test lasts for 20 minutes.

[0117] The composite fiber membrane regenerated according to the regeneration method of Example 5 is subjected to the above adsorption-regeneration process repeatedly, and after 20 times of repetition, the removal rate of the composite fiber membrane to the hydrogen fluoride gas and the hydrogen fluoride aerosol does not decrease. Thus, it is illustrated that the composite fiber membranes of Examples 1-3 have excellent regeneration performance and can be used repeatedly for many times.

[0118] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, and improvement made in the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A composite fiber membrane for removing hydrogen fluoride gas, characterized in that, The composite fiber membrane comprises a base layer and a microporous membrane layer; The base layer is obtained by modifying the base material with amino functional reagent dispersed in the base material under heat pressing treatment; meanwhile, one end of the amino functional reagent is embedded in the microporous membrane layer to bond the base layer and the microporous membrane layer; The base material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the content of acrylonitrile monomer in the base material is 10wt%-99wt%; The amino functional reagent is an amine compound containing at least two amino groups; The preparation method of the composite fiber membrane for removing hydrogen fluoride gas comprises the following steps: The base material is placed in a solution containing amino functional reagent to swell the base material, obtaining swollen base material; The microporous membrane material is covered on the swollen base material, and heat pressing treatment is performed to modify the base material with the amino functional reagent, meanwhile, one end of the amino functional reagent is embedded in the microporous membrane layer to bond the base layer and the microporous membrane layer, obtaining the composite fiber membrane for removing hydrogen fluoride gas.

2. The composite fiber membrane for removing hydrogen fluoride gas according to claim 1, characterized by The amino functional reagent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethylenenetramine and p-phenylenediamine; The microporous membrane material used in the microporous membrane layer is any one of polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane and polyvinylidene fluoride microporous membrane; the pore size of the microporous membrane material is 0.1μm-1μm.

3. The composite fiber membrane for removing hydrogen fluoride gas according to claim 1, characterized by The ion exchange capacity of the composite fiber membrane is 1mmol / g-6mmol / g; the resistance of the composite fiber membrane is <250Pa when the air linear velocity is 5.33cm / s.

4. A method for producing the composite fiber membrane for removing hydrogen fluoride gas according to claim 1, characterized by, The preparation method of the composite fiber membrane for removing hydrogen fluoride gas comprises the following steps: The base material is placed in a solution containing amino functional reagent to swell the base material, obtaining swollen base material; The microporous membrane material is covered on the swollen base material, and heat pressing treatment is performed to modify the base material with the amino functional reagent, meanwhile, one end of the amino functional reagent is embedded in the microporous membrane layer to bond the base layer and the microporous membrane layer, obtaining the composite fiber membrane for removing hydrogen fluoride gas.

5. The method for producing a composite fiber membrane for removing hydrogen fluoride gas according to claim 4, characterized by, The amino functional reagent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethylenenetramine and p-phenylenediamine; The microporous membrane material used in the microporous membrane layer is any one of polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane and polyvinylidene fluoride microporous membrane; the pore size of the microporous membrane material is 0.1μm-1μm; the resistance of the microporous membrane material is <200Pa when the air linear velocity is 5.33cm / s.

6. The method for producing a composite fiber membrane for removing hydrogen fluoride gas according to claim 4, characterized by, The heat pressing treatment is performed under the following conditions: The temperature is 60℃-140℃, the time is 1min-120min, and the pressure is 1MPa-3MPa.

7. The method of producing a composite fiber membrane for removing hydrogen fluoride gas according to claim 4, characterized by, The solution containing amino functional reagent is obtained by dissolving the amino functional reagent in a solvent; The mass concentration of the amino functional reagent in the solution containing amino functional reagent is 1%-50%. The solvent is at least one of water, methanol, ethanol, propanol, butanol, ethylene glycol and propylene glycol; the mass percentage of the solvent contained in the swollen matrix material is 10% to 60%.

8. Use of the composite fiber membrane for removing hydrogen fluoride gas as claimed in claim 1 as a fluoride ion adsorbing material for hydrogen fluoride gas treatment.

9. Use of the composite fiber membrane for removing hydrogen fluoride gas as a fluoride ion adsorbing material for hydrogen fluoride gas treatment according to claim 8, characterized by, The hydrogen fluoride gas contains hydrogen fluoride aerosol with a particle size of 0.3 μm to 1 μm.

10. Use of the composite fiber membrane for hydrogen fluoride gas treatment aspect as a fluoride ion adsorbing material according to claim 8 or 9, characterized in that, The regeneration method of the composite fiber membrane for removing hydrogen fluoride gas comprises the following steps: The inorganic alkali solution has a mass concentration of 0.5% to 10%; The used composite fiber membrane is immersed in the inorganic alkali solution, or the inorganic alkali solution is sprayed on the used composite fiber membrane; the used composite fiber membrane is used for adsorbing hydrogen fluoride gas. The inorganic alkali in the inorganic alkali solution is any one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

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